A new report from Reuters says that Apple has three manufacturers of this screen lined up: LG, making eight million a month; Japan Display, making eight million a month; and Sharp, making six million a month.

That means for the past couple months, the source for more than 25 percent of the iPhone 5 screens has been behind schedule.

One analyst quoted by Reuters says that almost all the phones sold so far have screens made by LG and Japan Display. If that's the case, then supply has indeed been severely constrained.

Correction: An earlier version of this post called the screen plastic. Then we called it glass. Both are wrong. By "screen" Reuters actually seems to have meant "display." I'm not a hardware specialist and I screwed it up. Sorry for the confusion.